<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        body {
            margin: 0;
            padding: 0;
        }
        
        .container {
            height: 400px;
            background-color: pink;
            margin: 0 auto;
            display: flex;
        }
        
        .left {
            height: 400px;
            width: 200px;
            background-color: aquamarine;
        }
        
        .content {
            height: 400px;
            background-color: tomato;
            flex: 1;
        }
        
        .right {
            height: 400px;
            width: 200px;
            background-color: yellowgreen;
        }
        
        .left,
        .content,
        .right {
            font-size: 70px;
            line-height: 400px;
            text-align: center;
        }
    </style>
</head>

<body>
    <!-- 
        三列布局主要分为两种
        第一种两列定宽，最后一列自适应（两列操作一样）
        第二种前后两列定宽，中间自适应
     -->
    <div class="container">
        <div class="left">左</div>
        <div class="content">内容</div>
        <div class="right">右</div>
    </div>
</body>

</html>